Devices for capturing and storing bodily fluid intravaginally are commercially available and known in the literature. Tampons are the most common example of such intravaginal devices.
The tampon is inserted into the human vagina and retained there for a time for the purpose of capturing and storing intravaginal bodily fluids, most commonly menstrual fluid. As intravaginal bodily fluid contacts the tampon, it should be absorbed and retained by the absorbent material of the tampon. After a time, the tampon and its retained fluid is removed and disposed, and if necessary, another tampon is inserted.
Commercially available tampons are generally compressed cylindrical masses of absorbent fibers that may be over-wrapped with an absorbent or nonabsorbent cover layer.
Friese et al., U.S. Pat. No. 4,816,100, discloses a fibrous tampon substantially surrounded by a nonwoven cover material. This tampon expands substantially uniformly over its total length when engaged by fluid. If the fluid is not uniformly or only partially applied to the tampon, increased fluid concentrations are developed in certain regions of the tampon which expand more quickly at these regions in comparison to other regions of the tampon. This leads to a substantially uncontrolled expansion of the tampon, depending only on the fluid concentration on and the fluid distribution to the tampon.
A drawback often encountered with commercially available tampons is the tendency toward premature failure, which may be defined as bodily fluid leakage from the vagina while the tampon is in place, and before the tampon is completely saturated with the bodily fluid. The patent art typically describes a problem believed to occur when an unexpanded, compressed tampon is unable to immediately absorb fluid. Therefore, it presumes that premature leakage may occur when bodily fluid contacts a portion of the compressed tampon, and the fluid is not readily absorbed. The bodily fluid may bypass the tampon.
To overcome this problem of premature leakage, extra elements have been incorporated into a basic tampon to try to control the flow of fluid toward the absorbent core and thereby control the expansion of the absorbent material of the tampon. In most instances, these elements are incorporated into or onto the tampon structure prior to or during compression of the absorbent material.
US Pub. No. 2001/0014348 (Schoelling) discloses a tampon including an absorbent body and a variably perforated or apertured cover. The cover includes a fluid-impervious plastic material in the form of a resilient three-dimensional web having a multiplicity of perforations. The perforations may be varied over the length of the tampon so that a differentiated expansion of the tampon while absorbing fluid is achievable. Preferably, the degree and size of perforations of the cover increases towards the withdrawal end of the tampon at least over a portion of its length. In this embodiment, fluid applied to the tampon is led into the direction of the withdrawal end and results in greater expansion towards the withdrawal end. The cover is attached to the absorbent material during formation and compression of the tampon.
US Pub. No. 2002/0133133 (Agyapong et al.) discloses a tampon having a width, length, and thickness. The tampon is compressed and upon fluid acquisition, provides expansion. The tampons of this publication exhibit an increased width (“X”) dimension force with a lower force exhibited in the thickness (“Z”) dimension, thereby purporting to provide increased comfort for the wearer. The pledget prior to compression may have shapes such as chevron-like, rectangular, trapezoidal, semi-circular, etc. Preferably, the pledget is shaped such that the middle region is a region having more absorbent material than the top of bottom regions. The pledget undergoes compression primarily focused in the X dimension rather than radially, axially or in multiple dimensions. The pledget material may undergo folding of the absorbent material in the X dimension. Since the human vaginal is typically a flat structure when at rest, the orientation of inserted finished tampon may be important.
Stokes et al. (EP 0 292 831) discloses a spiral wound tampon that is held together by a continuous line of adhesive at what is to be the withdrawal end. This allows for expansion at the insertion end and for removal of the tampon from the body cavity without telescoping. The withdrawal end remains in the original unexpanded state.
Others have included additional or secondary absorbent elements on the withdrawal string or even the finished tampon. See, for example, U.S. Pat. No. 3,101,714 (Penska) and U.S. Pat. No. 6,258,075 (Taylor et al.). Unfortunately, the secondary absorbent element may affect comfort of the wearer as it is close to vaginal opening.
Other may incorporate portions or projections that extend and contact the vaginal walls. See, for example, U.S. Pat. No. 4,212,301 (Johnson); U.S. Pat. No. 6,358,235 (Osborn et al.); U.S. Pat. No. 6,177,608 (Weinstrauch); and U.S. Pat. No. 6,206,867 (Osborn). None of the above mentioned disclosures disclose a predetermined expansion of the absorbent core in order to control the absorption of fluid.
While the prior art is replete with examples of sanitary protection articles is that capture bodily fluids intravaginally, these examples do not overcome the problem of premature failure often identified as by-pass leakage that commonly occurs while using internal sanitary protection devices. Many solutions to this problem have involved adding elements before the tampon pledget is compressed and hence the expansion of the tampon when body fluid contacts it is not controlled. The present invention details a way to control expansion such that only certain portions of the tampon expand when exposed to body fluid.